Tanning composition



Patented Oct. 20, 1925.

UNITED STATES 4 1,557,844 PATENT OFFICE...

CARL IMMERHEISER, 0F LUDW'IGSHAIEN-ON-T HE-RHINE, AND HUGO WOLFE, OF

, GERMANY, ASSIGNOBS, BY MESNE ASSIGNMENTS, TO BADISCH'E ANILIN & SODA FABRIK, 0F LUDWIGSHAFEN-O N-THEFRHINE, IBAVARIA, GERMANY, A CORPORATJ ION OF THE GRAND DUGHY OF BADEN.

TANNING COMPOSITION.

Ho Drawing. i

acids of crude anthracene, crude carbazol orj anthracene waste, in all save the color pro duced, give valuable results if employed for.

tanning skins or hides. The color ofthe leather produced is however so objectionable as to have practically precluded such leather from becoming commercial. This color is a dark brown of dull or grayish hue so different from that of leather tanned with vegetable-tanning agents as not to have gone into use either alone or in admixture therewith.

By the tanning agent below described we have succeeded in producing, within a small fraction of the time required by vegetable agents, leather tanned of the clear brown hues characteristic of the latter. To an ex-' pert in the art the difference in kind of color from that first referred to is such as to have proved vital to commercial success. either when our tanning agent is used alone or in combination with a-vegetable tanning agent.

It has been found that the said sulfonation product of crudeanthracene, including crude products .of anthracene or of carbazol or anthracene Waste and comprising, generally speaking, varyin higher'hydrocarbons and o carb azol, can

also be prepared in a form giving a far 1i hter colored leather and being therefore 0 an increased value. The new tanning composition can be prepared by treating the may also be employed. Another way of ob-" sulfonation product of crude anthracene with a. clearing agent. For examdple, chlorin or a hypochlorite may be add'e to the crude sulfonation product, or oxalic acid may be added either to the raw product or to the preparation obtained by the actionofchlorin, or hypochlorite. Formaldehyde taining the new form of the tanning preparation consists in sulfonating the initial ma- Application filed m 9,

mixtures of 1920. Serial m 395,127.

terial with chloro-sulfonic acid instead of with sulfuric acid. I The chloro-sulfonic acid can be employed at a moderate temperature and diluting means, such e. g. as nitrobenzene may be used along with-it. If desired, the roducts obtained with chloro- 'sulfonic acid may also be treated with a clearing agent of the aforementioned kind. The product obtained in one way or the other is distinguished by the following reactions. When hide is suspended for several days in its acidulated solution, it assumes a pure brown color in comparison w1th which the coloration produced with ordinary sulfonated crude anthracene is a dull, intensely grayish brown.

The product can be employed in the usual way in a slightly acid aqueous solution, preferably together with natural tanning extracts.

In order to further illustrate the nature of the invention, the following example is given to which, however, the invention is not confined. The parts are by weight.

Ewample 1.

An anthracene waste having the approxi= mate composition: per cent carbazol, 10 per cent anthracene, 20 per cent phenanthrene, 10 per. cent fluorene and similar hydrocarbons is heated, tofrom 100 to. 130

degrees centigrade, with concentrated s ll.-

fufl'e acid, in the proportion of 10 parts of the former to 12 parts of the latter, until the product is substantially soluble in water. The product is suitably diluted, freedfrom unaltered sulfuric acid by treating with lime, filtered and neutralized with soda lye. The solution of the sodium salt is then treated with sodium hypochlorite, while hot, or chlorin is introduced into the solution until its color is no longer improved, while the solution is ke t neutral,

or slightly alkaline by gradua ly-adding the required amou-nt of caustic soda lye.

I i 'Ewaxmple 2'. A

parts of crude anthracene, or of anthracene waste (residue from the purification of crude anthracene) or other mixtures of higher tar hydrocarbons, or carbazol are suspended in 200 parts of nitrobenzene, or

other suitable diluting agent, and 120 to 14:0

parts of chlorosulfonicacid are next intrm duced at temperatures below 100 degrees centigrade. .Stirring is continued for some hours until the product is entirely soluble in water.

- off with steam, or distilled ofi inwacuo; the

solution of the sulfonic acid mixture either wholly or partlyneutralized can now serve for tanning.

Oxalic acid may be added to the sulfonation products either directly or after the treatment with chlorin or hypochlorite, as

described in the foregoing example, in the proportion of say 20 to. parts to every ly and a solid leather showing a well mar-'- ketablecolor is thereby produced.

.We claimi 1. As a new composition of matter, a' new form of sulfonated crude anthracene which product on hide suspended in its dilute acid Then the diluting agent is blown solution slowly produces a pure brown coloration.

2. As a new composition of matter, sulfonated crude anthracene, with an addition of'oxalie acid which product on hide suspended in its dilute acid. solution slowly produces a pure brown coloration.-

3. As anew composition of matter, sulfonated crude anthracene, treated with chlorin and with an addition of oxalic acid which product on hide suspended in its dilute acid solution slowly produces a pure brown coloration. r

4. The process of'producing a synthetic material suitable for tanning hide which consists in' treating sulfonated crude anthracene, in a practically neutral solution, with active chlorin.

5; The process ofproducing a synthetic material suitable for tanning hide which consists in treating sulfonated crude an-' thracene in a practically neutral solution, witi actlve chlorin and then adding oxalic aci In testimony set our hands.

DR. CARL IMMERHEISER. HUGO WOLFF.

whereof we have hereunto 

